Many people experience problems falling asleep and want a medication that provides fast relief. There are many over-the-counter oral sleep aids that are available, however, they do not provide the fast action consumers desire. Standard oral dosage forms of diphenhydramine, a commonly used sleep aid, are swallowed and absorbed through the gastrointestinal (GI) system. Such forms take at least 30 to 45 minutes for the consumer to experience relief. The lag time between drug administration and onset of action can be attributed to dissolution in the GI tract and absorption into systemic circulation. Slow time to symptom relief for conventional oral dosage forms is often unacceptable to consumers.
Quick disintegrating tablets are an appealing alternative dosage form to consumers. Orally disintegrating tablets are formulated to disintegrate and disperse in the oral cavity prior to release of the active ingredient. The active ingredient can then be swallowed and later absorbed through the GI system like traditional oral dosage forms. Alternatively, the active ingredient can dissolve in saliva and be absorbed via the oral mucosa directly into systemic circulation. Such formulations are able to circumvent the first-pass metabolism effect, which increases the bioavailability of active ingredients.
However, current diphenhydramine products, including disintegrating dosage forms, are formulated to prevent dissolution in the oral cavity because it would cause an unpleasant bitter taste and numbing of the oral cavity. In addition, the biopharmaceutical properties of diphenhydramine at the pH conditions found in the oral cavity (pH 6.0 to 7.0) disfavors oral absorption. As a result, diphenhydramine in these products is swallowed and absorbed through the GI system like traditional dosage forms, which leads to a delay in symptom relief.
As such, there remains a need for improved options for fast acting diphenhydramine medications. In particular, there exists a need for a sublingual or buccal diphenhydramine composition that can dissolve quickly in the oral cavity and can be formulated to increase oral absorption.